This invention relates to an improved builder salt mixture for washing and cleansing agents containing water-insoluble, finely-divided aluminosilicates, carboxymethyloxysuccinates and small amounts of tripolyphosphates.
German published application DAS No. 2,412,837, corresponding to British Pat. No. 1,473,201 and U.S. Patent application Ser. No. 956,851, filed Nov. 2, 1978 (being a continuation-in-part of Ser. No. 800,308, filed May 25, 1977, now abandoned, which, in turn, is a continuation of Ser. No. 458,306, filed Apr. 5, 1974, and now abandoned), now abandoned in favor of Ser. Nos. 330,593, 330,594 and 330,645, all filed Dec. 14, 1981, describes washing, rinsing and cleansing compositions with a content of synthetic, crystalline alkali metal aluminosilicates which are suitable to completely or partly replace the phosphates usually contained in washing agent compositions. According to the teaching of these patents, the cation-exchanging aluminosilicates are used to improve and accelerate the washing process, preferably together with water-soluble sequestering agents. Optimum results, particularly as far as the secondary washing power is concerned, are obtained if the share of polymeric phosphates in the detergent is above 15%, and according to British Pat. No. 1,473,201, between 15% and 25%. In those cases where the law requires a lower phosphate or phosphorus content, problems may arise in hard water regions, since a lower phosphate content can cause, in frequently washed laundry, an insufficient secondary washing effect, and particularly causes fiber incrustations. The use of large quantities of other sequestering agents, particularly of aminopolycarboxylic acids, like nitrilotriacetic acid (NTA) or ethylenediaminetetraacetic acid (EDTA), leads to a satisfactory secondary washing effect, but it raises new, still unsolved sewage problems, for example, relating to a possible heavy metal re-mobilization. The same holds true for washing agent compositions containing large amounts of polyphosphonic acids, which may lead to a certain phosphate pollution, due to their phosphorus (P) content.
The German published application DOS No. 2,057,258, corresponding to U.S. Pat. No. 3,990,983, suggests using a carboxymethyloxy-succinate (CMOS) salt as a phosphate substitute in washing agent compositions. Such a substitution does not have the above-mentioned drawbacks. However in the interest of a satisfactory primary and secondary washing power, patentee recommends the use of larger amounts of phosphate, up to a ratio of CMOS to tripolyphosphate of 1:1, which obviates the desired aim of keeping the phosphorus content at a minimum.
German published application DOS No. 2,656,251 describes detergents which contain both CMOS and alkali metal aluminosilicates as builder salts, and which are said to be substantially phosphate free. In this patent, a comparison detergent is listed which is said to have improved whiteness power and contains 17% alkali metal aluminosilicates, 17% CMOS and 17.5% sodium tripolyphosphate (given in % by weight), the P-content of this mixture is undesirably high for the above mentioned reasons, so that it is unsuitable for the desired purpose.